The present invention relates to a device for controlling textile fibres floating through drawing cylinders of a drawing cylinder assembly in a combing machine.
A very important operation performed by a combing machine, during the spinning of cotton fibers, is that of assembling the slivers made by processing fiber laps coming from a drawing-assembling apparatus to transform said slivers, by a drawing operation, into a single even cross-section sliver.
This operation is conventionally carried out by a drawing assembly which is arranged on a side of the central body of the combing machine including therein a plurality of combing heads, said drawing assembly comprising a plurality of drawing cylinders therethrough the sliver to be drawn is caused to sequentially pass.
The cylinder assemblies are driven with different driving speed, to reduce the size of the sliver without interrupting its continuity.
During the above mentioned drawing operation, the floating fibers, i.e. the fibers starting and ending ends thereof are not engaged contemporaneously by a pair of subsequent rollers, must be properly controlled.
This problem has been solved in the prior art by using one or more movable rollers, of different geometrical configurations depending on the characteristics lengths of the fibers being processed.
However, in these prior art solutions, the fibers of the slivers being laminated are either arranged with a parallel sequential relationship, or they are arranged in a cascade relationship.
Actually, said sliver arrangements allow the floating fibers to be easily controlled by the mentioned movable roller devices.
However, as is known, the fibers exiting a combing machine have different characteristics, thereby the floating fibers control is much more difficult than the control of the fibers exiting a drawing machine or the like.
In order to better understand the nature of this problem, it would be useful to consider the method by which a combing machine, starting from the fiber laps, forms the sliver to be drawn.
For making the sliver, the combing machine combs the laps by portions, the so-called combing tufts, and for a full revolution angle of a circular comb.
Each combing tuft is overlapped, at least partially, on the preceding combing tuft, and then said combing tufts are pressed and joined to one another by stripping cylinders.
The above subsequent operations provide fiber slivers the floating fibers of which can be hardly controlled.
Thus, it has been experimentally found that the use of the above mentioned prior movable rollers, does not provide satisfactory results from a fiber sliver quality standpoint.